.k-backtop {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
    list-style: none;
    z-index: 10;
    position: fixed;
    right: 50px;
    bottom: 50px;
    height: 40px;
    width: 40px;
    cursor: pointer;
    display: block;
    overflow: hidden;
    border-radius: @radius;
    .k-backtop-content{
        background-color: rgba(0,0,0,.45);
        opacity: .5;
        height: 40px;
        transition: opacity .3s ease-in-out;
        text-align: center;
        line-height: 40px;
        &:hover{
            opacity: 1;
        }
        .k-ion-chevron-up{
            font-size: 20px;
            color: #fff;
        }
    }
}